For the first seven years of his life, Andrew struggled to tell his mother, Beth Patitucci, when he was hungry or when he wanted to sit on her lap. On an almost daily basis, his family and teachers at school would see Andrew cry, bite on his thumbs and lash out as if in pain. But he was unable to let them know what was wrong.

Andrew, who at age 8 is the size of a 3- or 4-year-old, has Cornelia de Lange syndrome, a developmental disorder that affects communication and social interaction. It is characterized by low birth weight, slow growth, distinctive facial features and small stature.

But a new iPhone application Andrew uses on an iPod has opened the doors to Andrew's mind.

Proloquo2go, the best-selling medical and educational app of 2009, has created a lot of enthusiasm among speech language pathologists, parents and people struggling to communicate. For some, like Beth and Andrew Patitucci, of Dresher, Pa., the app has provided a pocket-sized alternative to bulkier communication devices at a fraction of the cost.

"This was something that was affordable enough for us that we figured we'd give it a try," Beth said. "And if it didn't work out, we knew at least we'd end up with an iPod out of it."

Typically, Augmentative and Alternative Communication (AAC) devices with similar capabilities cost between $5,000 and $8,000. Proloquo2go is available online in the App Store for $189.99. Packaged with an iPod or iPhone and other accessories, the total cost is usually between $500 and $600.

The device is relatively simple to program, said Samuel Sennott, the 31-year-old co-creator of Proloquo2go and a doctoral student at Penn State University. Users press on icons, words, and phrases to create messages. Those messages are read aloud by the Proloquo2go software.

The app has also allowed certain users to bypass the bureaucratic channels necessary to receive more expensive devices. In many cases, insurance companies will only cover one AAC device every five years, and the process of getting funding for those devices can take months.

"The fact that users can get it commercially by going to Best Buy, Wal-Mart, Apple retail stores or any other electronics store is a dream come true for me," said Sennott, who's been working with children in special education since he was 19.

Proloquo2go App Helps People with Disabilities Communicate

A simple trip to the mall allows Patitucci to maintain her son's AAC device. When other AAC devices break, she said, "you usually have to send them in somewhere, and then you're going days and even weeks without communication that your son is now relying on."

When Patitucci heard about the app last year, she immediately purchased an iPod and the Proloquo2go software. Andrew had tried other AAC devices but his hands were too small to hold them. He also had trouble navigating the layers of information needed to make a command on other devices.

Patitucci removed all the original programming options from her son's iPod and left only two icons for him to press: "I'm hungry" and "I want to sit on your lap."

It took Andrew a few days to become acclimated to the software, but his learning curve has been steep. Since Andrew started using the device, his mother has added eight categories of words, emotions, phrases, songs and sentences for him to choose from.

"It has changed Andrew and many other people's lives," Patitucci said.

Before he started using the app, Andrew had what seemed to be chronic episodes of pain that flustered his parents and teachers. Andrew attends a private school where he receives one-on-one instruction. "In school, we thought he was having pain episodes," Patitucci said. "When he brought the iPod to school, his teacher noticed he was touching 'I'm hungry' an hour before they usually fed him."

Since then, his episodes of crying out in pain have reduced dramatically, she said.

But communications disease experts and AAC specialists note that Proloquo2go is not for everyone.

"There is no product that works for everybody," said Amy Goldman, associate director at the Institute on Disabilities at Temple University. "But [Proloquo2go] is demonstrating to the field and to consumers that it is possible to meet some people's needs at dramatically reduced cost."

Goldman called the app "revolutionary" because it offers powerful text-to-speech software on technology that is inexpensive and readily available. She still advises parents and people looking for communication devices to meet with AAC specialists to find products that fit their specific needs.

It's unclear what the presence of inexpensive software programs like Proloquo2go will mean for manufacturers of more expensive AAC devices.

Despite the presence of cheaper alternatives, the need for more specialized options will continue, said Judith Meyer, a spokeswoman for Prentke Romich Company, a leading manufacturer of AAC devices.

Some people, for example, can't hold an iPod or an iPhone, Meyer said. Others in the later stages of ALS will need eye-tracking software because they don't have the ability to move their hands.

"A lot of these devices are custom-designed and custom built for low-incidence populations," Meyer said. "It's not just a piece of hardware; it's not just a piece of software. There are lots of factors involved in the design and the manufacturing of these devices."

Sennott said he and co-creator David Niemeijer are currently working on a new edition of Proloquo2go that will be accessible to an even greater number of people. He said they are working to make the software easier to use for people with conditions like cerebral palsy, a neurological disorder that affects body movement and muscle coordination.

"We're trying to make this device accessible to people with various physical diseases," Sennott said.

And after a little more than half a year with Proloquo2go, Patitucci said her experience with the app has taught her a valuable lesson about her son.

"What I've learned is that he understands so much more than we thought he did," Patitucci said. "We were not sure where he was cognitively and just testing him and watching him navigate these buttons and find out what he wants to say, we found out that he has a lot more going on his head than we thought he did."

ABCNews.com contributor Matthew Nojiri is a member of the Syracuse University ABC News On Campus bureau.